I think one of the strengths of matrix (in addition to federation) is first-class bridging. I already communicate to several IRC networks, gitter and slack via matrix. I only have to use one matrix client and it enables me to communicate with people on several different networks/services. No monstrous electron apps that load the web UIs of several services in different tabs. The server-side in matrix handles the bridging and I can use any matrix client I like.